In a large bowl, add the flour, 1/2 cup of granulated sugar, unsweetened cocoa powder, baking powder, baking soda, and kosher salt.
Mix well until combined. Using a hand mixer or stand mixer, add the diced butter, and mix until you have a crumbly mixture. Add in the diced chocolate, egg yolks, and heavy cream, and mix until your dough has formed.
Divide the dough into 8 equal-sized portions of dough balls. Use a rolling pin, and flatten the dough into a 1-inch circle. In a shallow bowl, add the 1/2 cup of granulated sugar, and coat both sides of the chocolate biscuit.
Place the biscuits onto the parchment paper, and set the cooking time for 5-8 minutes, or when they are fully cooked. Remove and let cool for 20-30 minutes.
In a large mixing bowl, add the heavy whipping cream, and lemon juice, and whip until you make the homemade whipped cream.
Toss the strawberries with the granulated sugar, and then assemble. Place the shortcake on the bottom, add whipped cream, and sprinkle with some strawberries, then add another shortcake and add more whipped cream and garnish with more strawberries.